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Energy economy of the cells
Glucose --- ready cashLipids --- savings account
Fatty acids (from triacylglycerols) catabolization Citric acid cycle ATP
Acetyl-CoA
synthesis
Lipids
Catabolism of Lipids
Phospholipiase D
in spider and snake venom
Lipid products of hydrolysis
Lyse red blood cells
Prevent clot formation
Hormone-dependenthydrolysis of triacylglyerols
The formation of an acetyl-CoA in cytosol(activation step requires two ATP)
Role of carnitine in the transfer of acyl groups to the mitochondrial matrix
Carnitine translocase
Carnitine acyltransferase
-oxidation of saturated fatty acids
One cycle:2 C shorten1 acetyl-CoA formed1 FADH2 formed1 NADH formed
Degradation of stearic acid (18 C) through -oxidation
The energy yield from the oxidation of fatty acids
CH3(CH2)16C-S-CoA + 8FAD + 8NAD+ + 8H2O + 8CoA-SH
9CH3-C-S-CoA + 8FADH2 + 8NADH + 8H+
O
O
9CH3-C-S-CoA + 9FAD + 27NAD + + 9GDP + 9Pi + 27 H2O 18CO2 + 9CoA-SH + 9FADH2 + 27NADH + 9GTP + 27H+
O
17FADH2 + 8.5O2 + 25.5ADP + 25.5Pi 17 FAD + 25.5 ATP + 17 H2O35NADH + 35H+ + 17.5 O2 + 87.5ADP + 87.5Pi 35NAD+ + 87.5ATP + 35H2O
CH3(CH2)16C-S-CoA + 26O2 + 122 ADP + 122Pi 18CO2 + 17H2O + 122ATP + CoA-SH
O
one 18C fatty acid 120 ATP one 6C glucose 32 ATP
CytosolMatrix in mitochondia Citric acid cycle Electron transport chain
The balance sheet for oxidation of one molecule of stearic acid
CH3(CH2)16C-S-CoA + 26O2 + 122 ADP + 122Pi 18CO2 + 17H2O + 122ATP + CoA-SH
O
Metabolic water
The oxidation of a fatty acid containing an odd number of carbon atoms
-oxidation of unsaturated fatty acids
The oxidation pathways for polyunsaturated fatty acids
The anabolism of fatty acids
● Oxaloacetate and acetyl-CoA can not cross through mitochondria membrane but citrate can.
fatty acid synthesis in cytosol
The formation of malonyl-CoA --- the first step in anabolism of fatty acids
Acetyl-CoA carboxylase
Three proteins making up acetyl-CoA carboxylase
The first cycle of palmitate synthesis
ACP: acyl carrier protein
Fatty acid synthase
ACP has a functional group that is structurally similar to coenzyme A
The second cycle of palmitate synthesis in E. coli
In E. coli,multienzyme system
In eukaryotes,multifunctional enzyme
16C saturated fatty acid (palmitate)
A comparison of fatty acid degradation and biosynthesis
Chain lengthening beyond 16C
Pathways for the biosynthesis of triacylglycerols
Pathways for the biosynthesis of phosphoacylglycerols (I)
In E. coli
Pathways for the biosynthesis of phosphoacylglycerols (II)
In mammals
The interconversion of PE and PS in mammals
The anabolism of cholesterol
C2 C6 C5
C30
C27
● Most of the cholesterol formed in the smooth ER of the liver in mammals
The biosynthesis of mevalonate 2 acetyl-CoA
●This step is inhibited by high levels of cholesterol and is the major control point of cholesterol synthesis
●A target for drugs to lower cholesterol levels in the body
●lovastatin an inhibitor of HMG-CoA reductase
The synthesis of Squalene
The synthesis of bile acids from cholesterol
The synthesis of steroid hormones from cholesterol
The role of cholesterol in heart disease
● Deposition of cholesterol plaques atherosclerosis
● Cholesterol is transported by lipoproteins in bloodstream
● Lipoprotein aggregates are classified by their densities
LDL (low-density lipoproteins) particles
Lipids: cholesterol triacylglycerols cholerserol esters phospholipids
The fate of cholesterol in the cell
Proteins in LDL amino acidsCholesterol ester fatty acids + cholesterol
ACAT (acyl-CoA cholesterol acyltransferase)
HMG-CoA reductase
Synthesis of LDL receptors
lysosomes
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